Question: Solve for $x$ and $y$ using substitution. ${-4x+5y = -6}$ ${y = x-1}$
Answer: Since $y$ has already been solved for, substitute $x-1$ for $y$ in the first equation. ${-4x + 5}{(x-1)}{= -6}$ Simplify and solve for $x$ $-4x+5x - 5 = -6$ $x-5 = -6$ $x-5{+5} = -6{+5}$ ${x = -1}$ Now that you know ${x = -1}$ , plug it back into $\thinspace {y = x-1}\thinspace$ to find $y$ ${y = }{(-1)}{ - 1}$ $y = -2$ You can also plug ${x = -1}$ into $\thinspace {-4x+5y = -6}\thinspace$ and get the same answer for $y$ : ${-4}{(-1)}{ + 5y = -6}$ ${y = -2}$